Use of automated ambulatory-care encounter records for detection of acute illness clusters, including potential bioterrorism events.

The advent of domestic bioterrorism has emphasized the need for enhanced detection of clusters of acute illness. We describe a monitoring system operational in eastern Massachusetts, based on diagnoses obtained from electronic records of ambulatory-care encounters. Within 24 hours, ambulatory and telephone encounters recording patients with diagnoses of interest are identified and merged into major syndrome groups. Counts of new episodes of illness, rates calculated from health insurance records, and estimates of the probability of observing at least this number of new episodes are reported for syndrome surveillance. Census tracts with unusually large counts are identified by comparing observed with expected syndrome frequencies. During 1996-1999, weekly counts of new cases of lower respiratory syndrome were highly correlated with weekly hospital admissions. This system complements emergency room- and hospital-based surveillance by adding the capacity to rapidly identify clusters of illness, including potential bioterrorism events.

Two Outbreaks of Salmonella enteritidis Associated with Monte Cristo Sandwiches.

We report on two outbreaks of Salmonella enteritidis which occurred in 1992; both were associated with Monte Cristo sandwiches. The first outbreak, which occurred in Woods Hole, Massachusetts, was investigated as a case-control study, and involved 74 persons. The second outbreak, investigated as a cohort study, occurred in Brewster, Massachusetts, and involved 32 persons. Monte Cristo sandwiches were strongly implicated in both outbreaks; the odds ratio in the case-control study was 43, and the relative risk in the cohort study was 13. Food-preparation procedures were reviewed and food handlers were educated about safe food-preparation practices. Because of the short grilling time for Monte Cristo sandwiches, (usually several minutes) the eggs used in the preparation may only be partially cooked. As a result, this food should be viewed as high risk for S. enteritidis . Pasteurized eggs should be used to prepare Monte Cristo sandwiches, especially in a commercial setting.